ADVERTISEMENT. 



The extension of the scope of the National Museum during the past 

 few years, and the activity of the collectors employed in its interest, 

 have caused a great increase in the amount of material in its possession. 

 Many of the objects gathered are of a novel and important character, 

 and serve to throw a new light upon the study of nature and of man. 



The importance to science of prompt publication of descriptions of this 

 material led to the establishment, in 1878, of the present series of pub- 

 lications, entitled " Proceedings of the United States National Museum," 

 the distinguishing peculiarity of which is that the papers are published 

 in pamphlet form as fast as completed, and in advance of the bound 

 volume. The da te of publication being plainly expressed on each article 

 the ready settlement of questions of priority is assured. The present 

 volume constitutes the twelfth of the series. 



The articles in this series consist : First, of papers prepared by the 

 scientific corps of the National Museum ; secondly, of papers by others, 

 founded upon the collections in the National Museum ; and, finally, of 

 facts and memoranda from the correspondence of the Smithsonian In- 

 stitution. 



The Bulletins of the National Museum, the publication of which was 

 commenced in 1875, consist of elaborate papers based upon the collec- 

 tions of the Museum, reports of expeditions, etc., while the proceedings 

 facilitate the prompt publication of freshly-acquired facts relating to 

 biology, anthropology, and geology, descriptions of restricted groups of 

 animals and plants, the discussion of particular questions relative to 

 the synonymy of species, and the diaries of minor expeditions. 



Other papers, of more general popular interest, are printed in the 

 Appendix to the Annual Eeport. 



Papers intended for publication in the Proceedings and Bulletins of 

 the National Museum are referred to the Committee on Publications, 

 consisting of the following members : T. H. Bean, A. Howard Clark 

 (editor), Otis T. Mason, John Murdoch, Leonhard Stejneger, Frederick 

 W. True, and Lester F. Ward. 



S. P. Langley, 

 Secretary of the Smithsonian Institution. 



